Wear plate unit for scarifier shanks



y 1963 E c. DOBBRATZ ETAL 3,

WEAR PLATE UNIT FOR SCARIFIER SHANKS Filed Feb. 6. 1961 I] [fl/in C. DObb Z f j 12 James .14. 61am ATTORNEYS United States Patent 3,098,532 WEAR PLATE UNIT FOR SCARIFIER SHANKS Ervin C. Dobbratz and James A. Green, Modesto, Califi; Walta Dobbratz, administratrix of Ervin Carl Dobbratz, deceased Filed Feb. 6, 1961, Ser. No. 87,312 Claims. (Cl. 172719) This invention relates to scarifiers, and particularly to the shanks which support the digging points or teeth of the scarifier, and which shanks are upstanding above their teeth and are mounted in a fixed position.

When the shanks are so disposed, and with the scarifier in operation so that the teeth are substantially below ground, the disturbed dirt engages and relatively flows past the shanks in the zone immediately above the teeth. As a result, the shanks soon become worn away in such zone to an extent suiflicient to seriously weaken and ultimately cause the shanks to break.

It is therefore the major object of this invention to provide a wear plate unit which may be mounted on a conventional scarifier shank above the tooth to cover and protect the shank in the aforementioned zone of dirt abrasion so that the destructive eifect of the dirt on the shank is practically eliminated.

Another object of the invention is to provide a device for the purpose so constructed and arranged that it may be easily applied or removed upon removal of the tooth from the shank, and without any securing meansapart from the toothbeing necessary to hold the device in place.

An additional object of the invention is to provide a Wear plate unit for scarifier shanks which is designed for ease and economy of manufacture.

It is also an object of this invention to provide a practical, reliable, and durable wear plate unit for scarifier shanks, and one which will be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings:

FIG. 1 is a side elevation of a conventional scarifier shank with a tooth mounted thereon, showing the wear plate unit in operative position on the shank.

FIG. 2 is a fragmentary elevation of the shank, showing the wear plate unit in section; the scarifier tooth being removed.

FIG. 3 is a sectional plan on line 3-3 of FIG. 1.

Referring now more particularly to the drawings, and to the characters of reference marked thereon, the conventional scarifier shank 1 on which the wear plate unit is mounted comprises an upstanding bar portion 2 of rectangular form in section, and a forwardly and down wardly tapering foot 3. The forward straight edge 4 of the foot joins the forward edge 5 of the bar portion 2 with a short concave curve 6, as shown in FIG. 2, while the rear straight edge 7 of the foot joins the rear edge of the bar portion 2 with a convex curve 8.

A scarifying tooth 9 is wedgingly but removably fitted on foot 3 in the usual manner; said foot being the same transverse width as the bar portion 2.

The wear plate unit 10 comprises a collar 11 to lit the shank adjacent and mainly below the junction of the foot 3 and bar portion 2; said collar being disposed so as to be substantially at right angles to the forward edge 4 of the foot, as shown. At the sides the interior edges 12 of the collar are straight and parallel to the sides of the shank so as to slidably lit the same. The front in- Patented July 23, 1963 "ice terior edge 13 of the collar is shaped with a convex curve at the bottom to tit the curved edge 6 of the shank, as shown.

The rear interior edge 14 of the collar is shaped to generally tit the rear curved edge of the shank below the upper end of said edge, or where the latter joins the rear straight edge of the upper portion of the shank at a tangent.

Formed with the collar 11 at the front thereof and upstanding therefrom is a wear plate 15, the same width as the collar. The back edge 16 of this plate is tangent to the adjacent curved edge 13 of the collar so as to be adjacent and parallel to the upstanding edge 5 of the shank when the unit 10 is in place.

The front edge 17 of the plate 15, however, is straight from end to end, as shown in FIG. 2, thus making the plate 15 relatively thick intermediate its ends, and particularly in the zone of the shank-edge curve 6, which is the zone of greatest abrasion of the shank when unprotected. The Wear plate unit thus protects the shank against abrasion and wear in its critical area, not only at the front edge thereof but along the sides as well.

The wear plate unit is designed as above described so that it can only be slid up just so far on the shank, and when in its uppermost position the collar 11 is but slightly above the top edge of the tooth 9 when the latter is in its working position on the foot 3, as shown in FIG. 1.

The wear plate unit is thus prevented from downward sliding movement as long as the tooth is in place. Said unit can, however, be easily removed from or mounted on the shank once the tooth is removed.

From the foregoing description it can be readily seen that there has been produced such a device as will substantially fulfill the objects of the invention, as set forth herein.

While this specification sets forth in detail the prescut and preferred constructionof the device, still in practice such deviations therefrom may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described the invention the following is claimed as new and useful, and upon which Letters Patent are desired:

I claim.

1. A wear plate unit for a scarifier shank of substantially rectangular form in section and which includes an 'upper straight bar portion and a foot extending forwardly and downwardly from the lower end of the bar portion, the forward edge of the foot being disposed at an angle to the forward edge of the bar portion, there being a scarifying tooth rcmovably mounted on the foot and whose upper edge is below the upper end of the foot; the unit comprising a plate adapted to upstand in front of the shank from a point adjacent and above the upper end of the tooth and to follow and substantially engage such forward edges of the foot and bar portion to an upper end termination a predetermined distance above the junction of said edges, and a collar projecting rearwardly from the plate and slidably embracing the shank above and from a point adjacent the tooth.

2. A unit, as in claim 1, in which the plate is formed with a relatively thick portion intermediate its ends.

3. A unit, as in claim 1, in which the front edge of the plate is straight from end to end whereby the plate is thickest in the zone adjacent that of said junction of the forward edges of the foot and bar portion of the shank.

4. A unit, as in claim 1, in which the collar mainly engages the foot, the rear interior face of the collar sub- 3 stantially following the contour of the rear face of the foot below thejunction thereof with that of the straight bar portion of the shank.

5. A unit, as in claim 1, in which the collar is disposed on the shank in a-position to prevent upward 'slid ing of said' collar on theshank from a point adjacent the tooth.

References Cited in the file of this patent UNITED STATES PATENTS Harvey Dec. 10, 1872 McKenzie Nov. 21, 1911 Gustafson Nov. 19, 1940 Heckathorn June 13, 1961 Johnson Sept. 26, 1961 

1. A WEAR PLATE UNIT FOR A SCARIFIER SHANK OF SAUBSTANTIALLY RECTANGUALR FORM IN SECTION AND WHICH INCLUDES AN UPPER STRAIGHT BAR PORTION AND A FOIOT EXTENDING FORWARD LY AND DOWNWARDLY FROM THE LOWER END OF THE BAR PORTION, THE FORWARD EDGE OF THE FOOT BEING DISPOSED AT AN ANGLE TO THE FORWARD EDGE OF THE BAR PORTION, THERE BEING A SCARIFYING TOOTH REMOVABLY MOUNTED ON THE FOOT AND WHOSE UPPER EDGE IS BELOW THE UPPER END OF THE FOOT; THE UNIT COMPRISING A PLATE ADAPTED TO UPSTAND IN FRONT OF THE SHANK FROM A POINT ADJACENT AND ABOVE THE UPPER END OF THE TOOTH AND TO FOLLOW AND SUBSTANTIALLY ENGAGE SUCH FORWARD EDGES OF THE FOOT AND BAR PORTION TO AN UPPER END TERMINATION A PREDETERMINED DISTANCE ABOVE THE JUNCTION OF SAID EDGES, AND A COLLAR PROJECTING REARWARDLY FROM THE PLATE AND SLIDABLY EMBRACIONG THE SHANK ABOVE AND FROM A POINT ADJACENT THE TOOTH. 